Abstract: The microstructure of γ′ phase, the γ/γ′ lattice misfit, and partitioning behavior of alloying elements in four Ni-12.5%Al-8.31%Co-6.25%Cr-1.06%Mo-2.06%W-xTa-(3.12%-x)Ti (x = 0, 1.04%, 2.08%, 3.12%, atomic fraction) alloys were investigated using a scanning electron microscope, X-ray diffraction, a scanning transmission electron microscope, and first-principles calculations. The results show that as u/v (where u presents the atomic content of Ta, and v represents the sum of Ta and Ti atomic contents) increases from 0 to 1, the shape parameter of γ′ phase gradually decreases from 0.54 to 0.46. The absolute value of lattice misfit decreases from 0.245% to 0.198%. When u/v = 0.66, the γ′ phase reaches its maximum average size (233 nm) and volume fraction (74.8%). In all four alloys, Al, Ta and Ti have a preference for the γ′ phase, while Cr, Mo and Co prefer to the γ phase. In contrast, W elements exhibit a transition from initial preference for the γ' phase into the γ phase. Except for Co, other elements tend to partition to the γ' phase. However, due to the stronger partitioning driving force of Ta and W, Cr and Mo are displaced into the γ phase. In addition, compared with W, Ta possesses a higher partitioning driving force, leading to part of W being displaced into the γ′ phase and resulting in an “inverse partitioning” phenomenon of W.